<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Document</title>
  </head>
  <body>
    <div id="app">
      <h3>{{msg}}</h3>
      <input type="text" v-model="msg">
      <input type="text" :value="msg" @input="eventHandler">
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
      const app = new Vue({
        el: "#app",
        data: {
          msg:'别浪，猥琐发育！'
        },
        methods:{
          eventHandler(event){
              console.log(event.target.value)
              this.msg = event.target.value
          }
        }
      });
      </script>
  </body>
</html>